For more than a decade, scientists have been trying to solve the mystery of honeybees disappearing by the millions. There are many suspects, but one has become the focus of scientists and regulators worldwide. Over the past two months, several scientific studies have pointed to a family of pesticides—an insecticide widely used in agriculture but also found in backyard products.

The neurotoxic insecticide, chemically similar to nicotine, impairs honeybees’ ability to forage for pollen and lessens their ability to rebuild their colonies over winter. One scientific study pointed to more disturbing widespread ecological problems.

A four-year analysis by 29 scientists reviewing more than 800 peer-reviewed reports concluded for the first time that insecticides called neonicotinoids, or neonics for short, are “causing significant damage” to beneficial insects and are a “key factor in the decline of bees.”

In 2006, when the loss of honeybees in the United States was reported between 30 percent and 90 percent, the phenomenon picked up the name “colony collapse disorder.”

Various reasons have been given, including parasitic mites, pesticides, malnutrition and loss of natural foraging habitat, or a combination of those and other factors. But the threat posed by neonics was not among the top reasons beekeepers themselves reported for loss of their colonies last year, said Eric Mussen, an apiculturist at the University of California, Davis. Parasitic mites and starvation were cited as the top two causes.

While honeybee populations have slightly rebounded, their disappearance remains a mystery that confounds scientists and should worry the rest of us. About one-third of the food we eat—apples, melons, broccoli, squash and many other fruits, vegetables and nuts—grows with the help of bees.

Last year, the European Union restricted the use of neonics for two years. The U.S. Environmental Protection Agency is re-evaluating their use. The U.S. Fish and Wildlife Service recently said it will phase out the use of neonics in federal wildlife refuges in the Pacific Northwest and Hawaii.

Scientific research may take time to determine the exact cause, but there is a prime suspect that could be taken out or our backyards, and our fields and orchards.

We should have learned a few lessons by now in tinkering with the environment: Too often, we have introduced a solution to one problem only to create a ripple effect of harmful consequences.